Flexible pipe joint



Feb. 2, 1965 JOHNSON 3,168,334

FLEXIBLE PIPE JOINT Filed Nov. 28, 1961 2 Sheets-Sheet 1 FIG. 3

INVENTORI 6. 0. JOHNSON HIS AGENT 1965 e. D. JOHNSON 3,168,334

FLEXIBLE PIPE JOINT Filed Nov. 28, 1961 2 Sheets-Sheet 2 FIG. 2

INVENTORI G. D. JOHNSON HIS AGENT United States Patent 3,168,334 FLEXIBLE PIPE JOINT Glenn D. Johnson, Downey, Calif., assignor to Shell Oil Company, New York, N .Y., a corporation of Delaware Filed Nov. 28, 1961, Ser. No. 155,386 6 Claims. (Cl. 28555) This invention relates to a flexible joint for pipes and pertains more particularly to a flexible joint for largediameter pipes such as marine conductor strings that are employed in drilling offshore oil and gas wells.

In recent years methods and apparatus for successfully drilling wells at underwater locations has been developed. Most important have been the developments wherein it is possible to drill and complete a well on the ocean floor wherein the entire wellhead assembly is positioned at or near the ocean floor at a depth at least sufficient to avoid being a navigation hazard to ocean-going vessels. Offshore or underwater wells may be drilled from a suitable vessel such as a drilling barge or from a platform which has been floated into position over a selected location and then extend legs downwardly to the ocean floor so that the operating platform remains above the surface of the water to carry out drilling operations.

In drilling from a floating barge consideration must be given to the fact that a barge, even though anchored, possesses some movement. Thus, equipment such as drill stri gs and marine conductuor pipes extending downwardly from the barge to the ocean floor must possess some degree of flexibility so that they are not ruptured when the barge moves slightly off location. In general, drill pipe is of a diameter sufficiently small and is constructed sufliciently strong so that it possesses a relatively high degree of flexibility and is not subject to damage as much as other equipment. A marine conductor pipe however which is normally used to surround a drill string in offshore locations so that drilling mud may be returned up the annulus between the inner Wall of the conductor pipe and the outer wall of the drill string, is usually of considerably greater diameter and thus possesses little flexibility.

It is therefore a primary object of the present invention to provide a flexible joint for use in a marine conductor pipe depending from a drilling barge to the ocean floor to give suflicient flexibility to the marine conductor so that the barge need not keep the marine conductor in a vertical plane at all times.

A further object of the present invention is to provide a rugged flexible pipe joint capable of withstanding the forces to which a marine conductor pipe is subjected during oflfshore drilling operations.

Another object of the present invention is to provide a flexible pipe joint for a marine conductor pipe string, said flexible joint being provided with means for limiting the declination or angle of tilt of the joint so as to prevent rupture of the joint.

A still further object of the present invention is to provide a flexible pipe joint having a protective inner wall capable of protecting the sealing elements of the flexible joint, said protective wall being sufiiciently rugged to withstand the impact of drill bits, pipe string, or other Well tools that are normally run through a marine conductor.

These and other objects of this invention will be understood -from the following description taken with reference to the drawing, wherein:

FIGURE 1 is a diagrammatic view illustrating a drilling barge positioned above a drilling location at an offshore location where the wellhead assembly is positioned on the ocean floor;

FIGURE 2 is a longitudinal view taken in partial cross 3,168,334 Patented Feb. 2, 1965 section of one form of the flexible pipe joint of the present invention; and,

FIGURES 3, 4 and 5 are alternative arrangements of a protective liner forming the inner wall of the flexible joint.

Referring to FIGURE 1 of the drawing, a drilling barge 11 is illustrated as floating on the surface 12 of a body of water 13 above a drilling location wherein an underwater wellhead assembly 14 is positioned on the ocean floor 15. A large-diameter marine conductor pipe 16 is secured by means of a wellhead connector 17 to the wellhead assembly 14. The upper end of the marine conductor pipe 16 is secured in any suitable manner well known to the art to the barge 11, as by means of cables 18 and 19 which position the top of the marine conductor pipe 16 more or less centrally in a drilling slot 21 which extends through the barge 11.

Although the marine conductor pipe 16 is illustrated as being a continuous pipe or tubular element, it is normally made up of a plurality of relatively short sections of pipe secured together in any well known manner. Positioned in the marine conductor pipe intermediate the ends thereof are one or more flexible joints 22 and 23. During drilling operations a string of drill pipe 24 extends through a rotary table 25 and down through the length of the marine conductor pipe 16 and into the well. a

The flexible pipe joint assembly of the present invention is shown in FIGURE 2 as being provided with a pair of outwardly extending end flanges 26 and 27 which are fixedly secured between two sections 16a and 16b of a marine conductor pipe by any suitable connector means such as screw threads 28 and 29. Positioned between the end flanges 26 and 27 are a plurality of resilient compression rings 31, preferably made of rubber, with a rigid separator ring 3-2 positioned between each pair of compression rings 31. The compression rings 31 and the separator rings 32 have central openings therethrough substantially equal to the bore of the end flanges 26 and 27 and to the bore of the pipe sections 16a and 16b to which the end flanges are connected. The compressionrings 31 and the separator rings 32 are also normally in coaxial alignment with the flanges 26 and 27 and the pipe sections 16a and 16b.

The separator rings 32 are provided with a plurality of holes 33 while the compression rings 31 are provided with a similar set of holes 34 adapted to register with each other when in alignment with a'series of bolt holes 35 and 35a passing longitudinally as illustrated, through the end flanges 26 and 27. Extending through each set of holes 33, 34, 35 and 35a is a tie bolt 36 having bolt anchor means such as nuts 37 and 38 carried on the opposite end of each flange for securing the bolts in the flanges 26 and 27. The lock nuts 37a and 38a may be employed if desired.

The tie bolts 36 have a diameter less than that of the holes in the separator rings 32 and the end flanges 26 and 27 to permit slight movement of the bolt 36 in a direction normal to the axis of the holes 33 and 35. At least one of the bolt anchor devices, such as nut 37 forms a bolt take-up device when mounted on threads 39, the bolt take-up device being employed to apply tension to the bolts 36 to place the compression rings 31 in compression so that they are sealed in a fluidtight manner against the separator rings 32 and against the end flanges 26 and 27 at all times.

Each of the separator rings 32 extends inwardly toward the bore of the assembly preferably a greater distance than the compression rings so as to protect the latter from impact or rotational damage which may otherwise be effected by the drill string operating within the flexible'pipe joint. Variousprotective liners may be employed'onthe inner surface of the 'flexible' pipe-joint of the present invention to protect the compression rings and separator rings from wear by a rotating drill string or for protecting the'compression rings ag'ainst 'wear by an abrasive circulating drilling mud. 7

Referring to FIGURE 2, the protective' liner'may take the form of I a series of spacer rings 40 adapted to be seated on a pair of shoulders 4-1 and 42 formed on adjacent faces of a pair of adjacent separator rings '35. When the flexible joint is at its maximum angle of declination or tilt, as illustrated, the sh'oulders41 and 42 on 'theadjacent separator rings 35'are compressed tightly against the separator ring 40thus preventing further compression of the compression rings 31 on the-left-hand side of the flexi- "blejoint}as-illustrated. At-the sametime the outer surface of the spacer ring 40 presses against the separator ring so that it-does not move laterally.

When-the flexible joint is -at its greatest angle of tilt, P

as illustrated, the right-hand bolts are in tension between nuts 37 and 38 which bear against'flanges '26 and 27.

The bolt holes 35 are provided with-a convex washer 44 which-is welded to thetop ofthe flange 26 and constructed to mate with a'movable concave washer 45which is adapted to slide'over the'top faceofthe washer 44 when the ,bolt 36 moves later-ally. 'Theinner surface of each compressionrin'g 31'may be V-shaped, as at, sothat the lips of the'V cut *willbeforced outwardly byfluid pressure against'adjacent s'eparatorrings 32. Additionally, each spacer ring 40 may be provided with one or more fluid ports 47' so that fluid behind the spacer ring may flow into the bore of the assembly. The spacer rings 40 take the wear of a rotating element such as a drill pipe in the flexible joint and may be readily replaced when 'worn.

It is to be understood that various arrangements of protectiveliners on the inner surface of the flexible joint assemblyof the present-invention may be employed. For example, in FIGURE 3 'of the drawing, a spacer ring 40a is employed havinga diameter: greater than the inner diameter of the separator rings 32a, so as 'to'nest betweena -pair of separatorf rings 32a-while the compression ring prevents lateral movement of the spacer rin'g40a. In the arrangement shown in FIGURE 4, each'separator ring 33b is provided with suitable stop means which may be in the formof short ridgesor annular flanges extendingupWardIy and downwardly from either face of the separator rings 32b and positioned in from the innerface slightly to serve -as'lateral stop means-for the spacer rings 40b which-would limit the conipressionof the compression ring 31b. Y Y

' In the arrangement shown in FIGURE 5, -'t-he separator rings 32c are provided with upwardly and downwardly extendingflan'ges 48c on the innerface of theseparator rings 320. Thus, when a flexiblejoint employing the arrangement of FIGURE was at itsfmaximum angle of tilt, theadjacentflanges '48c'of adjacent separator rings 32c'would'be forced one against the othertopreventfurther compression of the--c6mpression-rings 310. This arrangement is not preferred since'the elementssubject to wear on the'in'nerface of the assembly could not replaced readily bnt it would be necessary to replace the entire set of separator rings 320.

I claimas my invention: 7 1. A flexible pipe joint assembly for flexibly connecting two sections of pipe together,- said pipe-joint assembly comprising a] pair of outwardly extendingend flanges, rr1eans on each end' flang'e' for "securing said flange coaxially to one pipe section, a plurality of resilient conipression rings arranged betweens'aidtendflangesya rigid separator ring positioned between each pair of 'con'ipressionrin'gs, said compression rings andsaid separator ringshaving sections,

connector means extending between said flanges and secured thereto for applying tension to place the compression rings in compression, the spacing between said flanges being adjusted so that the compression rings are in fluidtight engagement with said separator rings at all times, V a replaceable axially'flexible metallic wear liner carried by said assembly between the flanges thereof, said flexible metallic wear liner'including a spacer ring positioned betweeneach pair ofseparatorrings and between said separator rings and said flanges adjacent each compression ring, said spacer rings between said separator rings being of a size so limit the compression of said compression rings.

2. The apparatus of claim 1 wherein the internal diameter of said spacer rings is less than-the internal diameter of said separator rings.

3. The apparatus of claim 2 including shoulder means carried by said separator rings onboth sides thereof inwardly of said compressionrings, the ;diametrical spacing of said shoulder means being-substantially equalto but greater than-the external diameter ofsaid spacer rings forming stop means therefor.

4. A flexiblepipe jointassembly for flexibly connecting two sections of pipe together, said pipe joint assembly COITlPIlSIIlg apairof outwardly-extending end flanges,

connector means on'each end flange for securing said flange'coaxially to one'pipe section, a plurality of resilient compression rings arranged between said end-flanges,

a rigid separator ring positioned between each pair of compression rings, said compression rings and said separator'rings having a centre] opening aligned with the bore of said pipe sections, all of said rings having a plurality of bolt holes therethrough'adapted to be positioned in register,

'a' tie bolt'passin'g through each-of said'set of aligned bolt holes in said rings and secured at the ends to said flanges for applying tension to the bolt to place the compression rings in compression, the spacing between said flangesbeingadjustedso that the compression rings are in fluidtight engagement with said separator rings at all times,

a replaceable axially-flexible metallic wear liner carried by said assembly between the flanges thereof,

said flexible metallic wear liner including a spacer ring positioned between [each pairof separator ringsand between said separator rings and said'flanges adjacent eachcompression ring, said spacer rings having an axial dimension less than the space between the separator rings when the assembly is in'its unflexed position.

5. A flexible 'pipe. joint assembly for flexiblytconnectmg two sections of pipe togetherysaid. pipe joint assembly' comprising apair of outwardly-extending end flanges,

connector'means on each end flange for securing said flange coaxially to one pipe section,

a plurality of resilient compression rings arranged between said end flanges,

a rigid separator ring positioned between each pair of compression rings, said compression rings and said separator rings having a central opening substantials *ly equal to the bore of said pipe sections 'andnor- 'r'r'rally coaxiallyaligned'therewith, the'diameter of said central opening in said separator rings being less than that: in said compression rings, all of said rings and saidflanges'hav'ing a plurality of bolt holes therethrough adapted to be'p'ositioned in register,

"atie bolt passing'through each of said set of aligned 'bolt holes in said rings and said flanges, said tie: 'bolt having a diameter less than that of the-holes. in said separator rings and said flanges to permit slight movement of said bolt normal to the axis of said holes,

bolt anchor means carried at opposite ends of each bolt for movably securing each bolt to said flanges,

at least one of said bolt anchor means forming bolt takeup means for applying tension to the bolt to place the compression rings in compression, the spacing between said flanges being adjusted so that the compression rings are in fluidtight engagement with said separator rings at all times,

each of said separator rings extending inwardly toward the bore through said assembly a distance greater than said compression rings,

and shoulder means formed on both sides of the inner portion of each separator ring forming a spacer ring on the inner wall of each separator ring, said spacer rings limiting the compression of said compression rings.

6. A flexible pipe joint assembly for flexibly connecting two sections of pipe together, said pipe joint assembly comprising a pair of outwardly-extending end flanges, connector means on each end flange for securing said flange coaxially to one pipe section, a plurality of resilient compression rings arranged between said end flanges, a rigid separator ring positioned between each pair of compression rings, said compression rings and said separator rings having a central opening substantially equal to the bore of said pipe sections and normally coaxially aligned therewith, all of said rings and said flanges having a plurality of bolt holes therethrough adapted to be positioned in register, a tie bolt passing through each of said set of aligned bolt holes in said rings and said flanges, said tie bolt having a diameter less than that of the holes in said separator rings and said flanges to permit slight movement of said bolt normal to the axis of said holes, bolt anchor means carried at opposite ends of each bolt for movably securing each bolt to said flanges, at least one of said bolt anchor means forming bolt take-up means for applying tension to the bolt to place the compression rings in compression, the spacing between said flanges being adjusted so that the compression rings are in fluidtight engagement with said separator rings at all times, each of said separator rings extending inwardly toward the bore through said assembly a distance greater than said compression rings, shoulder means formed on both sides of the inner portion of each separator ring, and a spacer ring positioned on the shoulder means of each pair of separator rings and inwardly of each compression ring, said shoulder means forming stop means to maintain said spacer rings substantially coaxial with the bore of said assembly, said spacer rings between said separator rings having an axial dimension to limit the compression of said compression rings.

References Cited by the Examiner UNITED STATES PATENTS 789,948 5/05 Williams 138-139 973,238 10/10 Tideman 285163 1,153,824 9/15 Pierce 285106 1,948,211 2/34 Fritz 285223 2,256,386 9/41 Farrar et al. 138139 2,335,478 11/43 Bergman -a 285301 2,394,270 2/46 Swain 2851 14 FOREIGN PATENTS 101,531 7/37 Australia. 1,265,267 5/61 France.

737,355 7/ 43 Germany.

CARL W. TOMLIN, Primary Examiner. 

1. A FLEXIBLE PIPE JOINT ASSEMBLY FOR FLEXIBLE CONNECTING TWO SECTIONS OF PIPE TOGETHER, SAID PIPE JOINT ASSEMBLY COMPRISING A PAIR OF OUTWARDLY-EXTENDING END FLANGES, MEANS ON EACH END FLANGE FOR SECURING SAID FLANGE COAXIALLY TO ONE PIPE SECTION, A PLURALITY OF RESILIENT COMPRESSION RINGS ARRANGED BETWEEN SAID END FLANGES, RIGID SEPARATOR RING POSITIONED BETWEEN EACH PAIR OF COMPRESSION RINGS, SAID COMPRESSION RINGS AND SAID SEPARATOR RINGS HAVING A CENTRAL OPENING ALIGNED WITH THE BORE OF SAID PIPE SECTIONS, CONNECTOR MEANS EXTENDING BETWEEN SAID FLANGES AND SECURED THERETO FOR APPLYING TENSION TO PLACE THE COMPRESSION RINGS IN COMPRESSION, THE SPACING BETWEEN SAID FLANGES BEING ADJUSTED SO THAT THE COMPRESSION RINGS ARE IN FLUIDTIGHT ENGAGEMENT WITH SAID SEPARATOR RINGS AT ALL TIMES, A REPLACEABLE AXIALLY FLEXIBLE METALLIC WEAR LINER CARRIED BY SAID ASSEMBLY BETWEEN THE FLANGES THEREOF, SAID FLEXIBLE METALLIC WEAR LINER INCLUDING A SPACER RING POSITIONED BETWEEN EACH PAIR OF SEPARATOR RINGS AND BETWEEN SAID SEPARATOR RINGS AND SAID FLANGES ADJACENT EACH COMPRESSION RING, SAID SPACER RINGS BETWEEN SAID SEPARATOR RINGS BEING OF A SIZE SO LIMIT THE COMPRESSION OF SAID COMPRESSION RINGS. 